## SURF and OpenSURF

# This post has been moved to – http://blog.amitsarangi.me/surf-and-opensurf/

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Categories: C++, Documentation, GSoC 2010
Feature Extraction, OpenCV features, OpenSURF, Statistics, SURF

Very good post! Keep up the good work 🙂

Hi Amit, I had a question. After you extracted the interest points from two images, lets call them as model and target, what algorithm did you use to find the correspondences or matches? I’m really interested to know that, can you share that information? Also, please note that the results download link seams to be not working or broken.

Hi Vikram , thanks for pointing out. The download link is fixed now. Also regarding matching specific interest points, there is an inbuilt function in openSURF. Read my next post to this which explains how to use openSURF library : http://wp.me/pDkCO-4k . Get back to me if you still have any doubts.

Hi Amit, I had one more question, this time its about the SURF descriptors and also to do with programming. In your blog you have stated that the SURF descriptors can be extracted and saved, so we need not compute them every time. I want to do the same with the model images I have. I’m writing my project using C/C++, what is the best way to retain the descriptors? I’m currently having them as static Look-Up-Tables. I was curious to know if there are any other ways to do this?

Hi Vikram, you can look at the loadSurf() and saveSurf() method described there. the &ipts is the reference to the descriptor vector and filename is the name of the file you want to save to /load from.

Looking at the OpenSURF library (C# version), it appears that the “getMatches()” function is missing…

Am I missing something? It doesn’t appear to do much good without being able to test for matches between two images.

mm.. I will look at it , but I worked with C++ libs in which it was present.

Hi Chris,

do you have the getMatches() function in c# ???

Thanks

Amit can u pl tel me why integral image is constructed in beginning of algorithm…?

Please look at Notes on openSURF library where it is properly explained !

what actually an integrated image is…..? why it needs to be constructed…?

Hi Amit, im trying to adjust the openSURF code, although mine code is in MATLAB. r u free to tell me how can i change the no. of interest points? (tang0165@gmail.com) THX

The number of interest points in an image is not decided by you .

hi ,, i’m doin project on region of interest in matlab..can i get code for this pattern matching algorithm

I want to use open SURF for recognition in AR in iPhone.I don’t know how to get ModelView matrix of the object in camera frames. Please guide me that is there any utility function or any tutorial, code or book so that I could get the concept. Please guide me. Thanks a lot in advance.

hey im new on this blog… few days back i have started with the matlab basics… can i add the opensurf library in it… if yes do tell me the procedure thanks…

Check this out – http://www.mathworks.in/matlabcentral/fileexchange/28300-opensurf-including-image-warp

This should work for you.

thanks for the link…

Hi, thanks for that .

But I have a question, I’m planing to use this as a way to detect an object have two images from different degree, let’s say 8 degree. can this work ?!

thanks again

Yes :-). But I think you can use a better approach depending upon what you need.

Hello Amit, how to do the pattern matching?